Luis Reyes
Oct 13, at 11:00am ET
Solar panels have a big issue. They stop making electricity when the sun goes down, but that’s right when people get home, turn on the TV, and crank up the air conditioning.
For this reason, the solar farm that’s just starting to go up in Arizona’s Mohave County is getting its own batteries. And I mean a lot of them. ContourGlobal, the London-based power producer building it, says Project Sterling will have more than 760,000 solar panels and more than 300 battery containers. Tesla’s already signed up to buy about 90% of what it makes.
Sterling’s site is just off old Route 66, on the stretch between Topock and Kingman. Here, a new 5.2-mile road, Polaris Road, is being built to connect the two. Lake Havasu City, the Arizona town that famously bought London Bridge, is about 20 miles to the south, so a London company setting up shop out there feels about right.
The whole project occupies more than 2,000 acres in the Mojave Desert. (Yes, the county spells it Mohave and the desert spells it Mojave. You get used to it. I almost am.) For comparison, Sterling’s more than 760,000 panels would top the 700,000 we wrote about, which sit on an old Soviet firing range in Germany. Solar’s turned up in odder spots around Arizona, like over an irrigation canal south of Phoenix. But Sterling’s the classic version, with a whole lot of panels spread across open desert.
Figures: ContourGlobal.
Tesla’s deal is a power purchase agreement, which ContourGlobal announced back in July. A power purchase agreement is basically a long-term contract to buy a plant’s electricity at a price agreed up front. It lets a company like Tesla secure a lot of clean power without having to build or operate the plant itself. (Sorta Elon Musk’s whole thing, if you ask me.)
Under the deal, Tesla gets about 1 terawatt-hour a year, which ContourGlobal says is around 90% of what Sterling will produce. A terawatt-hour is a billion kilowatt-hours, and the kilowatt-hour is the unit on your power bill. Tesla also receives the renewable energy certificates that accompany that power, which are essentially receipts that let a company count the electricity as clean.
So where’s all that power going?
No spam. Unsubscribe anytime. Privacy policy (opens in new window)
Sterling plugs into lines run by the Western Area Power Administration, the federal agency that sells the power from Hoover Dam, among other things. It also has firm rights to send power over the lines into California, and it’ll be pseudo-tied to California’s grid. A pseudo-tie basically lets a plant that’s physically in one grid operator’s territory act like part of another’s, so California’s grid operator can treat Sterling as one of its own plants. Trade publication pv magazine reported in July that the power’s meant for Tesla’s California operations.
ContourGlobal hasn’t said which Tesla sites will use it, what Tesla’s paying, or how many years the contract runs, and I couldn’t find anything from Tesla on it. This would probably be good to know, but I wouldn’t hold my breath for a price, either, since companies tend to keep those numbers to themselves. And if you’re Tesla, you apparently don’t like sharing data at all.
Antonio Cammisecra, ContourGlobal’s president and CEO, said in the company’s groundbreaking announcement that “our teams engineered the project around the specific needs of our customer.” ContourGlobal bought Sterling while it was still in development and reworked it to meet Tesla’s needs, so it’s basically a made-to-order power plant.
Cammisecra also says Sterling will be able to deliver power for up to 16 hours a day. Basically, the panels handle the daylight, and the batteries handle the evening.
Sterling’s battery system is rated at 360 megawatts and 1.4 gigawatt-hours. If you’re wondering why a battery needs two ratings, think of megawatts as horsepower and gigawatt-hours as the size of the gas tank. One tells you how hard the battery can push, and the other tells you how long it can keep that up. Put it all together and Sterling’s batteries can run flat out for about four hours.
Add a long day of sunshine to about four hours of battery, and you can see how the company gets to 16. I’d guess 16 is a best-case number, though, since a December day in the Mojave is a lot shorter than a June one.
The batteries are lithium iron phosphate (LFP) with liquid cooling and built-in fire protection. LFP cells hold a little less energy than the nickel-heavy ones in a lot of EVs. They’re a lot less likely to catch fire, though, which you’d probably want if you’re parking more than 300 containers of them in the desert. As far as I can tell, neither of ContourGlobal’s announcements names a battery supplier. Tesla, the customer here, sells its own shipping-container-sized Megapack batteries to power companies, so I’m pretty curious whose cells end up inside.
You’ll see Sterling described both ways. And they’re both right. Solar panels produce direct current, and Sterling’s panels are rated at 509 megawatts. The 450 is what the plant can actually send to the grid once inverters turn that into alternating current, the kind that comes out of your wall outlet.
The panel maker doesn’t seem to have been named either, so I can’t tell you how big each panel is. Divide 509 megawatts by 760,000 panels, though, and each one works out to somewhere around 670 watts.
ContourGlobal’s July announcement had one line that’s easy to skim past. It said work on Sterling had already started last year through “off-site physical work of significant nature,” including the purchase of major equipment.
I doubt that wording was an accident. The IRS uses almost the same phrase, “physical work of a significant nature,” as its test for when a solar project has officially started construction. For a plant that won’t be finished until 2028, that start date decides whether it can still claim the federal tax credits for wind and solar that Congress started phasing out last year. I couldn’t find anything from ContourGlobal on whether Sterling is claiming them.
If you’re planning a Route 66 road trip, the stretch between Topock and Kingman will probably be a little busier than usual for a while. ContourGlobal expects an average of about 400 people working on Sterling during construction, and it’s aiming to have the plant up and running in 2028.
Don’t bite your tongue. Speak up.
Luis Reyes · Oct 10, 2026
Luis Reyes · Oct 1, 2026
Chema Bonilla Díaz · Sep 23, 2026
Olivia Richman · Sep 18, 2026
Luis Reyes · Oct 6, 2026
Luis Reyes · Oct 2, 2026
Chema Bonilla Díaz · Oct 13, 2026
Luis Reyes · Oct 13, 2026
Olivia Richman · Oct 13, 2026
Luis Reyes · Oct 13, 2026
Olivia Richman · Oct 13, 2026
Autonotion is the English-language automotive editorial by Autonocion.com — car news, reviews, and industry analysis for American readers.
Other links
Company
Subscribe
Get the latest car news in your inbox:
By submitting your email you allow autonocion.com to send you news or promotions. More info

source